CISTERN 8. 



91 



. The above cut represents the sectional view of a filtered 

 cistern, with a brick wall partition in the middle and the 

 box of charcoal and sand at the bottom, with alternate layers 

 of each. The pipe at the left leads from the roof, and the 

 one at the right connects with the pump. With this style 

 of cistern properly constructed, no one need be in want of 

 pure wholesome water. 



To construct a filtering cistern to furnish pure water 

 for domestic use. 



RULE. Divide the cistern into two equal compartments 

 by a wall of brick or stone, open at the bottom to the 

 height of about six inches, and water-tight thence to the 

 top. Let one compartment be for receiving the water, 

 and the other for containing it when filtered and ready for 

 use. Put alternate layers, 6 inches deep, of gravel, sand, 



